Former Owner
- Khouri, Elias Alexander1
- King Lawrence Parker1
- Klaus Dieter Dahmen1
- Lambach Abbey1
- Laurence Kirby1
- Laurence Vaux1
- Laurence William Hodson2
- Leo Olschki2
- Leonello d'Este, Marquis of Ferrara1
- Leopold Gruber1
- Llewelyn Lloyd-Mostyn, 3rd Baron Mostyn of Mostyn1
- Long Island Historical Society, Maine1
- Lorenzo Antonio da Ponte1
- Lorenzo de Olivera1
- Louis Charles Karpinski1
- Louis César de La Baume Le Blanc3
- Louis H. Silver11
- Louis Herbert Gray1
- Louis Loewe1
- Louis Lucien Bonaparte1